That's... just a prison cell like you'd find in many places.

Looking at that picture I'm unsure what makes it "nice" except for the fact that it looks somewhat freshly built.

Cells are cells. What really differentiates prisons is everything around them and what amenities and workshops are offered.

There are definitely bad prison cells. Multiple beds per cell, overcrowded, old, cold, hot, no windows etc.

hole in the floor instead of a toilet, and that hole can not be closed, spreading incredibly awful smell 24 hours per day.

Consider yourself very lucky you have never been to a prison (or jail) in New York. I assure you the cells look nothing like this.

Well but that's like saying consider yourself lucky to not have been to a Russian or Nigerian jail. American prisons are famously bad and known for it worldwide. I'd compare this cell to a cell in a country that doesn't have a completely broken judicial system and then yeah, it's nothing that special. It's a cell, maybe the bed looks "nice" but at the end of the day it's a place of incarceration not a hotel.

It has a window, that already makes it better than a cheap hostel room I stayed at once.

Go look at US prison cells, they're so much worse, there's often no separation between the toilet and the sleeping area.

Well I meant in contrast to US prison cells, since I assumed most users here are from the US, maybe I'm wrong on that front.